bergman



Dec. 27, 1927.

L. H. BERGMAN PULVERIZED FUEL FURNACE Original Filed Jan. 7, 1920 2 Sheets-Sheet 1 r pu till!!! Twfe 1J3 a ,Ji w

Ii llirvba Dec. 27, 1927. R 16,828

L. H. BERGMAN PULVERIZED FUEL FURNACE Original Filed Jan. 7, 1920 2 Shggts-Shget 2 A wig Reissued Dec. 2?, F32? UNITED STATES PATENT OFFICE.

LABS HUGO BERGMAN, OF CHICAGO, ILLINOIS, ASSIGNOR BY HESNE ABSIGNHENTS, TQ RAYMONB BESS. ENGINEERING CO., OF CHICAGO, ILLINOIS, A CORPORATION 03 ILLINOIS.

PULVERIZED-FUEL FURNACE.

firig'inal No. 1,421,898, dated July 4, 1922, Serial No. 350.015. filed January 7, 1920. Application for reissue filed December 24, 1923. Serial No. 682,536.

This invention retntcn to pulverized l'nel l'urnarwa, more particularly those in which scparulo sircuins oi air are introduced tlicrc in. one to propcl the fuel into the l'urnacc. and thc other to supply the ncccssat achli tional oxygen tor complete combustion.

l'owelorctl incl. cvcn when crushed that 8011: will pass 100 nicsh, takes an apprccia blv t me to burn so that provision must be nuulc to allow sutlil-icnt time for complete combustion.

Not only is it n-vrcs il'yto allow tilnc tor romluwtinn. but it is also desirable to provi lc means for intimately mixing the powltc i-il tool with tho air in which it is burnt.

tine oi t c o iiccts, therefore, of the prosout lll lfinl fill is to provide a method of and nicuns whereby the poivtiercd fuel and air arc. caused to travr-l over a path of suf 'cicnt lcngth under conditions which bring about complete corribustion of the fuel and the precipitation of iucoinhust'hlcs as ash.

Another object of the invention is to provide means for intiinatcly mixing the pow- (lcred fuel with the air in which it is burnt...

A furthcr ohjcct of the invcntion is to providc improved means for collecting the ash produced by the burning, of the fuel.

Other and further important objects of the invention will be apparent from the di$ closures in the drawings and specification.

lhc invcntion (in a preferred form) is illustrated in the drawings and hcrcinafter m rn fully described.

()n the drawings:

Figure l is a front elevation of a furnace and boilcr constructed in accordance with the prcsent invention, onc-halfsof the figure being in section on tho lino 1'-l of Fig. 2.

Fig. 2 is a Section on. the line 2-2 of Fig.5. l. "1 i Fig. S3 is. a section on the line 3---3 of Fig. 2. the nozzles being shown in elevation.

Fig. +1. isu vertical section through one of thc pnlrcrizcd l'uel injectors.

As shmvn on thedrawingsz Th0 t'urnaces shown form the lire-boxes o a series of water-tube boilers, each denoted by the reference numeral 1, mounted in brickwork 2 in the usual way. The furnace itself consists of a fire-brick chamber 3 having an arched roof 4, a front wall 5, pnd 2. bottom 6. the rearward part 7 of which slopes upwardly towards the water tubes of the boilers. Powdered incl, usually coal (lust. is stored in a. series o l' hoppers ll arranged along the front; of the boilers. The lower parts of these hopper: counnuuh rate with worn] fending devices 10 adapted to supply powdered fuel at a uniform rate to vertical pipes 11 which carry the fuel to fuel nozzles 12. The necessary air for injection of the powdered fuel and for the c01nbustiou thcrcof is supplied from a blower or fan {not shown) through a conduit 13 from which lead branch connections 14: to the respective fuel nozzles.

Tho construction of each nozzle. is shown more particularly in Fig. 4 in which it is ccn that the nozzle COIIIPIISES a chamber 15 at its: upper end to which air is supplied through one of the pipes 14. From the lower end of this chamber extend curved concentrically arranged pipes 16 and 17. Centrally arranged in the top of. the chamber i5 is the end of the pipe 11 to which is connected by suitable means a. conical jet 18. by which powdered fuel is directed into the inner of the two concentric pipes. The air flowing from the chamber 15 downwardly through the pipes 16 and 17 is divided into two concentric streams, the outer one heinn of air only while the inner one consists of air cariying with it particles of coal dust. It will be seen that slow moving currents of air will be sufficient to carry the fuel into the furuacc, on account of the peculiar construction and disposition of the burners.

l licsc nozzles are arranged in thc side walls 21ot'tlu-chan1bcr3 adjacent to its upper edge so as to direct strcains of air inwardly, downwardly and forwardly as indicated by the arrows in the various ligurcs. By forwardly I mean toward the front wall of the furnace. that is the wall opposite to the draft outlet: and by iuwurrllv I intend away from a side. that is one of the walls transverse to said front wall. ;\(llllji?llt each nozzle the shin wall is thickened. as at? 22. so that the entire nozzle is tlll'0illllflttl by fire brick and tllcl'ell) prom-ted against the extreme heat of thc furnace. Pairs of nozzles are cmplqyed to produce converging and mutually impinging streams of air with the result that each of the streams is thoroughly broken up, thereby intimately mixing the air introduced merely for the purpose of completing com- Ill to the boiler.

bastion with the streams of air which act to propel the pulverized coal into the turnace. In this way a very satisfactory inter-mixture of the fuel and the air is obtained. Further, by directing the streams of air downwardly and forwardly and thereafter rearwardly and upwardly to the discharge flue or draft opening the particles of fuel are retained in the chamber 3 sutliciently long either to burn completely therein or to burn to such an extent that combustion is completed as the gases pass through the tubes 8 of the boilers and any heavy particles from the nozzles gravitate into the lower or rearwardly moving portion of the return bent stream to enhance the chances of combustion being complete. One other result of causing the gases to flow around this circuitous or return bent path is to aid in the separation of the ash which is thrown against and collects upon the inclined bouom T of the chamber. The ashes may be removed from time to time through doors :20 arranged along the lower edge of the front wall 5. Sight holesv 19 may also be provided in this front wall so that the operation of the furnace may be observed.

From the foregoing it will be observed that the body of fuel mixed with air is introduced into the combustion zone in such menu that under the combined forces of the ex. ring st ream or streams. gravity and the draft. the ruel in combustion takes a curved or circuitous course, first passing laterally and downwardly away from the outlet, then bendingback horizontally beneath the incoming streams. and then curving upwardly and rearwardly towards the outlet During this entire course it. is not guided by the chamber walls but follows a course determined by the balanced forces of the initial velocity. gravity, and the draft so that there is no forceful contact with the furnace walls and bottom. and the stream of combustible fuel is enveloped by a body of air which when introduced into the furnace is substantially free from fuel and which. following the course of the fuel stream, supplies additional oxygen thereto, tends to protect the walls and bottom of the furnace. tends to insure against direct impingement. of the fuel stream tl reagainst, and acts to cool the incombustib es naturally in a molten state, so that the deposit of such incomhustibles is in the form of ash which can be readily removed. A pocket, of some depth is. in ettect. proridqldat the bottom,of the furnace below the course of the fuel stream through which the slag particles may fall and congeal and in which they are collected.

Preferably, as shown in the drawings, the fuel particles and flames pass through the combustion chamber in two streams which remain separate until after they have revertod whereupon they move in juxtaposed relation below the incoming fuel streams and eventually merge in their movement to the draft outlet whereby the incoming: Incl is subjected to the heat of the juxtaposed and merged flame streams in a manner calculated. to give most complete combusl ion of the tool as well as the combustion of the maximum quantity of fuel for a combustion ehamber of given size.

1 am aware that many changes may made and numerous details co. strut-thin may be varied through a wide range wi isout departing from the principles of this in.- vention. and I. therefor-c do rnot purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. In a furnace {or pulverized feel. a combustion chamber. downwardly "rccteel fuel conduits. air chambers one ear litlllt lllgi the month of each fuel conduit. mixture conduits leading from each of said air chain hers into the combustion chamber, said mix lure conduits being curred so as to deliver streams inclined downwardly and toward thel front of the combustion chamber. said inclined streams converging toward the trout of the combustion chamber. an outlet at the rear of said combustion rbanibr-r. means for conveying pulveriz d fuel to said tool mar rlnits. and means for convey} air under pressure to said air chambers.

2. In a furnace for pulverized fuel. a romlmstion chamber, tlmrnwardly directed fuel conduits. air chambers one surroundingthe mouth of each fuel conduit. mixture conduits leading from each of said air chain here into the combustion chamber. s, id mixtnre conduits being curved so as to. deliver streams inclined downward and toward the front of the combustion chamber. said inclined streamsconverging tovard the front of the combustion cham er. air conduits sillrounding'; said mixture conduits re ertirrly. whereby the streams delixored each consist. at the point of delivery. of a rent stream of mixture of air and fuel and at enlar surrounding stream of air relatiwl free from fuel. an outlet at the of aid com bastion chamber. means for eonreying pulverized fuel to said fuel conduits. and means for conveying air under pressure to said air chambers 3. In a furnace for burning pulverized fuel, having an arch, a wall at one end of the arch. a draft opening at the other end. and a boiler arranged to be heated by products of combustion passing through said draft outlet; i'ncans or projecting a stream of fuel under the arch in the direction toward said wall. so that under the com bined actionot the force of the incoming stream. gravity and the draft. the fuel in combust on takes a return heat course. first away from and than tmvard the. draft, without impingement upon the arch. wall or bottom of the furnace. with the returning stream below the inroming stream.

4. In a furnare to! burning pulverized fuel having an arch, a wall at one end of the arch. a draft opening at; the other end. and a hoiler arranged to lll heated hr products of eoaihuetion nawing through Raid draft utlet: ltic'di t girojerting a stream of fuel into the i'urnaeu in a diagonal direction downwardh and away from the arch and toward wall so that under the muuhiu wl all force of the incoming A ream. I t the draft, the fuel in t l'lllllh'l ljll talle a return hent course, lilai a a a v from and then toward the draft without impingement upon the arrin wall or bottom of the turna o. with the returnil'ig' stnam li ltfll' the incoming StreaaL .2 in a fortune for burning: pulverized fuel 1 no; on ireli. a wall at one end of the arrh. a imit and a hoil r aria lltlF of roniha opening; at the other end. god to in heated hy prodnaswiuu' through said tllzii l outlet; mean; or projecting c nverging rtreanw of fuel under the Zll't'li in the direction toward ru tl wall So that under the romhiued mliolt wt the forre oi the incoming stream. ,z'r;alrit and the that"!- the fuel in romhu li n talus return bent courses. first away from and then toward the draft. without izoi ngrinr it upon the arch, wall. or bottom of he i llflllitt. with the ret rni g stream helow the mounting etreams.

(Z. in a furnace for burning pulverized fuel harm; an arch. a wall at one end of the arrh. a draft open ng at the other end, and a hoilrr arranged to he heated by prodlV'in ot' romhuation passing through said draft outlet; means for projecting converg in; .atrrama ot fu l into the furnace in diagronal llllP'VlllHlH ihmnwardls, away from the Ell't'li and toward said dill. F0 that under the eomhineil action of the force of the in coming streams. gravity and the draft, the fuel in roinhuation takes return hent courses. first away from and then toward the draft. without iuniin 'ennnt upon the arch. wall or liottom of the l'uriuu-e. with the returning str am hehiw thriui-oluing streams.

T. lna l'urnarn for burning; pulverized fuel. liming: an ll.t'll. a wall at one end of the arrh. a llral't oprning'at the other end, and a hoiler arranged to he heated by products of combustion pasing through said draft outlet: means for projecting a stream of fuel under the arch in the direction toward said Wall so that under the combined aetionof the force of the incoming Stream, gravity and the draft, the fuel in combustion takes a return bent, course, first away from and then toward the draft, Without impingement; upon the arch, Wall or bot tom of the furnace, with the returning fuel having an arch,

stream heiow the incoming stream, and means for introducing into the furnace: a bOtlj of air, substantially free from fuel. which cnrelops and follows the fuel stream in its course through the furnace.

8. In a furnace for hurn ng puiverimul a walia: one end of the arch, a draft opening; at! the other end, and a hoiler arranged to he heated by praai nets of eomhuatiou pas 'through sun! draft outlet. means for ing atream i of fuel under tin. ar l direction toward said wail the roinhins'd action of th to; coming etrratm ,Q'l'tltlhl a. t in fuel in roinhustiou i'alies return lwut' (-HHNn tiret away from and then toward the drain without mpingementi upon theareh. .valhor hotloru of the furnace. with the returning stream below the incoming streams, and means for introducing into the furnace hodie-- otair enhatantially free from fuel. which envelop and follow the ti el streams in their rouraea through the furnace.

U. In a furnace for burning pulverized l'iu-l having an; arch. a wall at one end of the arrln a draft opening at the other end. and a boiler arranged to he heated by prod nets of romhuetidn passing through said draft outlet; fnleaits: for projcrting a stream of fuel and an enveloping stream of air substant'iallvtree from fuel, into the furnace in a direction down 'ardly away from the arch and toward eaid wall, so that under the comhinerle'ution of the force of the incoming: stream, grairity and the draft, the fuel in eomhustion takes a return bent; course first away from and then toward the draft, witlh out impingement upon the arch, wall, or bottom of the furnace, with the returning stream below the incoming stream.

10. in a furnace for burning pulverized fuel having an arch a wall at one end of the areln a draft opening at the other end. and a boiler arranged to be heated by prod nets of combustion passing through said draft outlet; means for projecting converging strnuns of fueh together with streams of air enveloping stlitl fuel streame respectiveil v. into the furnace. in diagonal direetiom downwardly away from the arch and toward said wall so that under the combined artion of the eourer of the incoming streams, gravity. and the draft. the fuel in combustlbllf takcarcturn hent courses first; away from and then toward the draft, without impinging upon the areh, wall or bottom of the furnace, with the returning stream below the incoming streams.

llflaMethod of burning pulverized fuel which consists in projecting into a combu tion zone having a draft outlet. in a directiorgaway from said draft; outlet, a stream of'ful mixed with air at such velocity that the qombined forces of the ingoing stream,

at: in

' d v/iii ga-mizy [Hl i the limit, pi'adum a movemeni ni llw burning iuei in a eurvesi return bent uaah 1w :1 irmn, (lewnwardly and. back tward ihrlimit euiiet, Wiii'l the returning r the rng mg stream and with mgemem age the ennfim'ng walls ,l i-wiiihusliun 20112. Mr-thud 0f imenis'w gmlverized fuel vwmiwis in prujeeiing into a comlme- :r rim: Lame Mixing: a draft euilei, in a direc- H m arm;- frmn sairl (,ii'fifi outlet, a stream l'm i iflHil wilh a r at snrh veioeity and iine ni' he draft that the cumui' the iuguing stream, gravity ail: produce a movement of the in :1 rrn eii Semi-n bent path downwardly and back inward "uiiet, wifh the reiusning: Firearm irlg siliziin and withem: imi;; met the confining @2315 e? inn zone, and inlruriueimr mini:- iienai 2i iiilli'illi" free rein fuei, 31m Lifii'iiiiirzone. an that saiii adriii' l inilnws the cam; a? he prnviiie :uhliiionui mx gmi mini Mme-sphere sum-main inie which the invari- :1? in in": precipiiaieii ml]. 13. Me z'ning QUlVQFiZGLi 122i whim iii 3'%i iiiilg inin 1L combustiun 21m Living :1 draft Glitlfii, in a direction awn from said draft outlet, converging streams 5f iuel mixed with air at such velom it and angles ta iiie line of draft that the :JOmiiinmi fnrees nf the ingoing streams, gravity and the (weft przulnce a, n'iovelnent nf he lmrnmg fuei in wired paths awn freer dswm'vziriily :ii'ni men heck owuni the draft oath-h wit i'he returning stream be the ingninsg i 3315 wifhout impingement en the confining weils of said ('UITibliS-= lien mne,

bustihie p burning pairerizeri fuel which fiil" pmjeeti'ng inie a comims time mire having :1 draft outlet in a direcaiwzirrliy and away from said draft r'iifrfklil nf fnei mixed xviih all? at iii 'ty hat the itljmbined forces of the ditiunul oxygen and relativeiy e001 atm0sphere surrounding the fee stream mm whicla file incombustibies pass an as in be recipitated as ash.

151 Meihod of burning pulyerized fuei which mneims in projecting into a wz'niiue llull zone having a draft outlet, in :1 direc (ion away from said nniiei, 2i sire-run 0% fuel mixed with air surrounded by an annuiar stream of air unmixed with fuel at such velneity and angle tn the line elf draft that the emulsified forces of the ifl-LGfliilig \li'iillh gravity and he hull ii'mluce a monument of the imrning iuei in a ve l-mi hem path first away from and then imvaral the draft wallet with Hie returning stream helpw the inguing atreum. and nut 0*? runtzurt with the rnnlining walls f he Mullins-- tiun zone.

inn Zone having a Graft outlet :1 piurnliiy' of mnrvrging streams 0i fuel mixed with air, in ilireetions away frmn iiiu til'liii mstiel at such velocity and angles i'i-ijam the hue ut' draft that the CUIIEiJiPEWi {0115135 if the iii l'ijllig streams, gariiy and the limit. produce a mmement of the burning fuei in return heart paths, with the returning stream below the ingning streams first zumy irum and then tmrurd the draft euilet and in he center portion of the ruurhustion lune on; of mutant with the confining weiis therunf.

17. Method of burning icllii'fiiidfll fuel which consists in projefling inn,- :1 eezniims tion zone having a draft outlet a plurality m eei'sverging streams u'f fuei in (iiTC-T away from he Lirafl outlet anxi art such \ei ity and angles from the line of dra hurt the cemhineel forces of he ingeing streams, gravity and the draft produce a mnveiuent 0f the burning fuel in streams which separateiy revert in substantially U-: .ape and then advancing in juxtaposed EFirLLiOjl merge and pass to {the draft, uutiet. i

18. Methori of burning pulverized incl which ennsists in projecting: into a ilfllnbids' tron zone having it (lrafi uutiei'. a pluraiuy of cunverging streams emf fuel. each with an CERTIFICATE OF CORRECTIGN.

Reissue Patent No. 16,828. Granted December 27, 1927, to

LARS HUGO BERGMAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as fc-Hows: Page 4, line 72, for the word "steam" read "stream"; and that the said Letters Patent shoufd be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 31st day of January, A. D. 1928.

M. J Moore.

Seal. Actin Commissioner of Patents. 

